Enabling Temporary Links and .htaccess Rewrite Rules

Good afternoon everyone, I have just purchased a VPS as I am a Freelance Website Developer and plan to grow in the next year or so; hence the upgrade as I need stability. I use a bespoke PHP content management system which uses several Rewrite Rules via .htaccess and since migration I cannot get the websites to work properly due to the Rewrite Rules not functioning. I had problems with the temporary URLs too but have finally got them working by using OpenLiteSpeed and by changing a few other things. If anyone can give me some advice on how I can get this .htaccess file working as it should, I would be very appreciative. I've spent the entire day researching and I'm no better off! Kind Regards, Dan