SEO - migration to a new site

We have a well established site but needed updated for mobile devices. So we are launching a lighter version in wordpress of that old site in joomla. The site is in spanish and english.

I need help:

With redirections as many pages don´t exist in new site
SEO in general

Step #1: Create a List of Keywords
Step #2: Analyze Google’s First Page
Step #3: Create Something Different or Better
Step #4: Add a Hook
Step #5: Optimize For On-Page SEO
Step #6: Optimize For Search Intent
Step #7: Focus on Content Design
Step #8: Build Links to Your Page
Step #9: Improve and Update Your Content