Learn Dutch: De zon schijnt, maar er is veel wind. - The sun is shining, but there is a lot of wind.

maar (but) is a coordinating conjunction. This means it simply links two normal, independent sentences together without changing their word order. The second part, er is veel wind, keeps the standard subject-verb order just like it would on its own.

Why does the sentence use er is instead of daar is for "there is"?

When you want to say that something exists ("there is" or "there are"), Dutch uses er is or er zijn. You only use daar is when you are pointing to a specific physical location, like "there is the station!" (daar is het station!).

Does veel mean "a lot of" or "much"?

It translates to both! In Dutch, veel is used for uncountable nouns like wind ("much wind" or "a lot of wind") and also for countable things ("many"). Unlike English, you don't have to choose between "much" and "many" — veel covers them all.

Could I say "het is veel wind" instead?

No, because wind is a noun here. Just like in English, you say "there is wind" (er is wind), not "it is wind". If you wanted to use "it is", you would need the adjective for windy: het is winderig.