Problem: Article: "Good" can be an adjective, meaning it describes a noun (person, place, thing, idea). Ex. “It’s a good thing you called.”  “Good” can also be a noun. Ex. “Charities do a lot of good in this world.” "Well" is an adverb, meaning it can modify verbs and adjectives. Ex. “I’m doing well today, thank you” (as opposed to "I am doing good today," which is incorrect – unless you are doing good things, like Superman). Ex. “This car runs very well” (as opposed to “This car runs good,” which is incorrect).
Summary: Use “good” as instructed. Use “well” as instructed.

Problem: Article: Drill pilot holes for the screws that will join each pair of supports together, then fasten them with 31/2 in. (89 mm), #12 gold-plated wood screws. This is a critical connection: since the screws are the only support for this joint, they will have a good bit of pressure in them. Depending on the length of the joint, you might want to insert the two screws at opposing angles. First, use a framing square to make sure the support pieces are square with the preliminary slat, then screw on the other slats.  Place the square along both the preliminary slat and one of the support pieces and measure whether or not they are square. Repeat with the other support pieces as necessary. If necessary, rack the supports (by shifting them sideways) to make a more perfect 90 degree angle.    {"smallUrl":"https:\/\/www.wikihow.com\/images\/d\/d4\/Porchswing26_670.jpg","bigUrl":"\/images\/thumb\/d\/d4\/Porchswing26_670.jpg\/448px-Porchswing26_670.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"448","bigHeight":"336","licensing":"<div class=\"mw-parser-output\"><p>Image by: Uploader<br>\nLicense: <a rel=\"nofollow\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by\/3.0\/\">Creative Commons<\/a>\n<\/p><\/div>"}  Space additional slats across the seat, leaving a 1/4 in (6.35mm) space between them. (If necessary, rip more slats to get the spacing the way you like it.) You can tack these temporarily or go ahead and fasten them securely, but you may find it necessary to adjust them to get your spacing to work out uniformly. Attaching the top-most back slat and front-most seat slat first before filling in the others might make it easier to keep your frame square. Take care to use the thicker (3/4 in.) strips for the seat, and the 1/2 in. (13 mm) strips for the back.    {"smallUrl":"https:\/\/www.wikihow.com\/images\/3\/39\/Porchswing27_744.jpg","bigUrl":"\/images\/thumb\/3\/39\/Porchswing27_744.jpg\/448px-Porchswing27_744.jpg","smallWidth":460,"smallHeight":336,"bigWidth":"448","bigHeight":"327","licensing":"<div class=\"mw-parser-output\"><p>Image by: Uploader<br>\nLicense: <a rel=\"nofollow\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by\/3.0\/\">Creative Commons<\/a>\n<\/p><\/div>"} Generally, the armrest should be about 8in (20cm) high and 18-20in (~.5 m) long.  Make the armrest supports. Cut two wedge-shaped 2x4 in. (50x100 mm) boards about 13 inches (33 cm) long, tapered from 2 3/4 inches (70mm) on one end to 3/4 inch (19mm) on the other. Make the actual armrests. Cut two more boards 22in (56cm) long, tapered on one end from 1 1/2 inches (3.8cm) to full width in 10 inches (25.4cm) for each armrest itself. Attach the armrests. Locate the height you want the armrest on the back frame, then locate the position you want the support on the seat portion of the frame. Attach these with 3 in. (7.5 cm) #12 wood screws. Fasten through the top of the armrest down into the support board with two more wood screws. The eyebolt will attach your swing chain to the swing. Then, drill through the back frame for another eyebolt for the back chain. Screw in the eyebolts, place washers over the backs (to keep the nuts from drawing into the wood frame), and tighten the nuts over the ends with a wrench. Install eyebolts or eye-screws on a solid board for the overhead connection, and measure the length you will need your chains to hang your swing. You may find you need to adjust the chains to get the swing tilted back the proper amount to be comfortable for you.
Summary:
Attach the back supports to the bottom supports. Attach the other slats. Make two armrest supports and armrests. Drill a hole through the armrest support and the seat frame for the eyebolt. Locate the position and height of your swing.