Here’s a helpful discussion about the ways to samadhi according to the suttas:
Personally I have my difficulties with the Anapanassati Sutta (MN 118) or the Satipatthana Sutta (MN 10) as I find they are not self-explaining and are more a summary of the whole meditation path than an actual practical guide. The “gradual training” on the other hand is more straight forward I think:
If you look for meditation masters that represent the spirit of the Dhamma more than a scholarly exposition, I would recommend Ajahn Dtun - The Sacred Equation
Best wishes for the practice!