Hello Paul,
These videos show some of the ways to use your DNA to find your relatives https://www.wikitree.com/g2g/1054650/how-does-help-you-register-gedmatch-your-gedmatch-wikitree
Please also see the following on how to get your Y haplogroup from your AncestryDNA results and associate your Y haplogroup with your direct paternal line in WikiTree: https://www.wikitree.com/g2g/800267/are-you-a-male-who-has-tested-with-ancestrydna