What are the best settings for fastest downloads?

This depends on many things but mainly your internet connection so you will have to elaborate quite a bit to get a meaningful answer.

To answer that question, you have to understand the behaviour of a swarm of peers.
If all want to download only, and nobody uploads, the overall DL speed is very low.
The more everybody uploads, the more does everybody get, meaning You Too.
So - the solution is: Put your Tixati to Maximum and Unlimited Upload First,
and you can see after a while (e.g. 30 Minutes, depending on the size),
that also your DL speed increases significantly.

If you are on ADSL connection however, with far lower upload than download bandwidth, you'll have better speeds when upload is limited to 70-80% (see step 1. from Optimize Tixati help guide). Best practice is to set two bandwidth profiles: one for downloading, with limited upload, and the other for seeding, with unlimited or slightly limited upload. Mark these profiles as Downloading and Seeding Defaults, Tixati will switch between them automatically.

Your settings can have some effect, but download speed is mostly affected by external factors over which you have no direct control.

torrent file sharing is a community affair based on sharing, which means uploading too.

Focus on increasing your UPLOAD speed. That build a stronger sharing community and will impact your download speeds in both short and long term.

Put your Tixati to Maximum and Unlimited Upload First  how do you do that what settings sso i cahange or whatever?

God in heaven help me i went to the duide link you need an enfineering degree to figure that out im lost