Need help with changing button names in Wordpress and formatting questions?

https://citruskill.com/

My site is nearly finished, though there are a few things I wish to do. I want to change the name of the "select options" button, which is a leftover from another theme I previously used, to buy now, as it leads to the product page.

I also wish to know how to put the sidebar on the front page on the left side, instead of the right side?

One more thing, I want to know how to fix the odd spacing on the top since I want to make the logo more centered?

Thanks