How can I tell what my race is? Please answer?
Why would you know that? You're from several countries that already have a history of successive peopling. DNA testing companies can give you a rough idea, but they are not reliable for small percentages. By the way, blind experiments have often proven detailed results inaccurate. What about just accepting you're another proud example of 21st-century earthling?
Take a DNA test with Ancestry.com or 23 & me. They will give you your ethnic breakdown.
You're a mutt. Being from Guyana you could be part Indian (you say you are), African, native to one of the local tribes, or even European. If you want to know the breakdown, then pay the $50 or so to do a 21 and Me, or similar, DNA test.