You certainly don’t need to correct everything before getting started! We are all a work in progress. These resources are designed to optimize performance and address issues as they arise but don’t worry about fixing everything before getting started. Make a checklist of things you would like to work on and just spend a little bit of time each day addressing 1-2 of those from your list at a time. Don’t try and fix everything at once. The most important thing is to keep moving and start exercising.