it looks like to me the base is a standard mount that is used for satellite dish antennas.
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If so, the bolt on the left goes all the way through and is not meant to be tightened down, it's just what the mast pivots on, and you will collapse the mast if you try to over tighten it. The the ones on the left on the semicircular cutout are the ones you want to tighten down. There should be one on each side, so you tighten each one separately to hold the mast securely to the base, and as they don't go all the way through, it doesn't collapse anything.