Yes this procedure is correct *if*
you want to create a precession corrected Solar Return in the Tropical zodiac.
This procedure essentially uses a Sidereal Zodiac to find the exact time of return (as against using the more common Tropical Zodiac), then casts a tropical chart for that (Sidereal Zodiac return) time, so in essence, mixing and matching two distinct systems. Which is fine if you know what you are doing.
In detail, you
(1) change the zodiac used to Fagan Bradley (which is a Sidereal Zodiac)
(2) Find the time that the Sun returns to the exact point it occupied in your natal chart in *this* zodiac. This should be on or near your birthday give or take a day maximum.
(3) Note the time. (you don't interpret this sidereal zodiac chart at this point at all. you only want the time)
(4) Then switch zodiac back to tropical.
(5) Create a chart for the noted time *and location you occupy at that point of time*, not where you are now. So if you plan to be in New York at this time, the Solar Return chart uses New York and not your natal location)
(6) Interpret this chart as your Solar Return chart for that year.
I don't know if the step by step instructions for astro.com are correct, - I use Solar Fire - but this is the essence of what is happening.
In my opinion, as said above, this mixing and matching of concepts from two distinct systems should be avoided by beginners, but it is ok if you know what you are doing.
That said, no harm in casting this chart and seeing if it is accurate for you. If it works great, you can worry about internal details later.
PS: I am a beginner too, and I use one zodiac (Fagan Bradley, the sidereal zodiac used above to find the time of the return) consistently and don't mix and match. Someone more expert than me can probably give you better advice. So take all the above with a pinch of salt.