First, Welcome to the village. You will find a lot of great folks here to help in your journey of scrolling.
Cutting 90* turns in thicker wood, 1/2" 3/4" is basically done the same as thinner pieces. I normally use a #5-UR blade. If you are using a bigger blade you can back out of the corner and cut back into the waste area opening up the space for the blade to turn. When the hole is large enough turn your piece and continue with your cut. My preference is to anchor the wood with one finger and gently turn into the cut using my other hand. Always turn into the waste area. There are some good videos on YouTube that you can watch that may help. The main thing is to be patient especially when learning and don't get frustrated. It is a learning curve we have all gone through, in time you will develop the skills and abilities to do almost any project. Remember to enjoy your time with your saw.
One a side note. Try and stay away from the blades at the big box stores. I use Flying Dutchman, others use Olsen and Pegasis blades.All are good blades and all serve a purpose. You will discover what blades you like and work for you.
Have fun and enjoy.
Hope this helps some.