Can anyone explain the ditto strats that pokeguy used instead of walking to the center and doing everything

Here: https://docs.google.com/document/d/1LeWs_N381jNpOYV3cQAIDdSBci0aACWB-ihEQS7dg74/edit?usp=sharing

If you have Red version, there's currently no setup to manip ditto (I'm trying to find one tho), so Blue is the only one used for this route atm.

There are many people more qualified to answer your question than me, but since I have also recently started to run this category and had the same problem I think you may benefit from another rookie's perspective on the matter. Everything you do from 'power on', matters, first to consistently get the Ditto encounter and then to capture it. My guess is that you're just not doing things as quickly and precisely as they should be done. I'd suggest to watch some run with inputs showing(Shirokami_Cusp's works) and compare them to what you're doing. What helped me was:

• make sure you don't move before saving in Cerulean Cave
• make sure you're hard resetting and not soft resetting
• for the frame perfect walk-up to Ditto you can generally change the direction key when the character has begun walking onto the last tile before turning(you can't hit any walls or stand still, that will mess up the manip)
• follow the exact path as in the runs(and the tutorial)
• after getting the Ditto encounter try to dismiss the "Ditto has appeared" box as frame-perfectly as possible, it takes a bit of practice
• what I found helpful was to hold down+a during the cry, up+a immediately after the menu click and keep holding up+a until it gets in the ball(holding it that long is not necessary, but it prevents you from releasing it too early) I'd advise you to just play the run not paying attention to the timer up until that point, save after entering the cave and just practice this segment until you get it. The frustrating bit is that you'll only know you're doing it right AFTER you've done it right at least once, so up until that point you'll constantly be wondering if there's something you're still doing wrong. It just takes practice I guess, but if my 'advice'(re-iterating the tutorial, let's be honest) doesn't help you then maybe somebody with a bit more experience will be able to assist you. Keep trying, you'll get it eventually!