Your panels should come with MC 4 connectors (male and female), and for series, simply daisy chain them (say, + to -) together…Various gauge and length wire pairs (with + & - MC 4 connectors on their panel connect end) are available on Amazon…FWIW, there’s really no advantage to mono vs poly except that mono has a slightly smaller footprint resulting from mono’s slightly increased efficiency…Your free to mix panels (and footprints), but it’s best overall that voltage ratings remain closely similar (more critical with parallel than when in series)…Happy Harvesting :)
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