redirecting everything through htaccess

hi

I have a non-Wordpress website that I would like to redirect entirely to Wordpress using .htaccess but I don't know how to do this.

The domain name will remain the same, but this time it will point to a new website that I have created on a different hosting account from a different hosting provider.

Here are 3 questions whose answers will help me know how to proceed

1. Is it better (in terms of SEO and clean redirection) to do this through the use of any Wordpress redirection plugin or must this be done through the htaccess file? And if it does make a difference which method I use, why is it better to do one over the other?

2. If I take the htaccess redirection route, what exactly do I need to type in the file? Also, do I need to redirect each page individually or is there a command or something that will redirect the whole thing in one shot?

3. Also, which htaccess file should I write the redirection code in: the one located on the current account or the one located on the new folder where I set up the website on Wordpress?

Please give some instructions as I never understood the deal with htaccess

Thanks