Learn Hardcore German: Am Strand trage ich immer Sonnencreme, damit meine Haut geschützt bleibt. - At the beach I always wear sunscreen so that my skin stays protected.

In German am is simply the contraction of an + dem. Here an with the dative case indicates a location, so am Strand literally means “at the beach.” Both an dem Strand and am Strand are grammatically correct, but am is much more common in everyday speech.

Why is the word order Am Strand trage ich immer Sonnencreme... inverted, and could I say Ich trage am Strand immer Sonnencreme instead?

German uses the so-called V2 (verb-second) rule: the finite verb must be the second element in a main clause. When you begin with an adverbial phrase like Am Strand, that counts as the first element. That pushes the subject (ich) after the verb (trage). You could also say Ich trage am Strand immer Sonnencreme, which is perfectly fine—it simply places the subject first and the location later, changing the emphasis slightly.

Where does the adverb immer (always) go in a German sentence, and why is it placed between ich and Sonnencreme here?

Immer is an adverb of frequency (time). In German’s middle field, the usual order is: subject – time – manner – place – object (roughly). In Am Strand trage ich immer Sonnencreme you have:

First element: Am Strand (place/time)
Verb: trage
Subject: ich
Adverb of frequency (time): immer
Object: Sonnencreme
This places immer right after the subject. If you began with the subject (Ich trage immer Sonnencreme am Strand), immer would still follow the verb in second position.

Why do we use damit to link ...trage ich immer Sonnencreme with meine Haut geschützt bleibt? What does damit do?

Damit is a subordinating conjunction meaning “in order that” or “so that.” It introduces a purpose clause when the subjects of the two clauses are different (main clause = ich, subordinate clause = meine Haut). A subordinate clause with damit always has the finite verb at the end.

Could I replace damit with um ... zu instead, and if so, how would the sentence look?

You can use um ... zu only when the subject of both clauses is the same. If you want to keep ich in the subordinate clause, you could write:
Um meine Haut zu schützen, trage ich immer Sonnencreme am Strand.
Here um + infinitive (zu schützen) expresses purpose. You cannot use um … zu if the subordinate clause has a different subject (meine Haut).

In damit meine Haut geschützt bleibt, why is bleibt at the very end of the clause?

Any German subordinate clause (introduced by a subordinating conjunction like damit) puts the finite verb in the last position. Non-finite elements (like participles) come before the finite verb.

What is actually happening with bleibt geschützt? Is this a passive construction?

This is the so-called Zustandspassiv (stative passive). Bleiben + past participle (here geschützt) expresses that something remains in a certain state. It is not the dynamic passive (Vorgangspassiv) with werden, which would emphasize an action. You could say meine Haut ist geschützt (“my skin is protected”), but bleibt geschützt adds the idea of continuity—you stay protected.

Why is the verb tragen used here for sunscreen—wouldn’t auftragen (to apply) be more precise?

The typical German collocation for “apply sunscreen” is Sonnencreme auftragen (a separable-prefix verb). You would then say trage ich Sonnencreme auf (with auf at the end). However, speakers sometimes shorten it to trage ich Sonnencreme (“wear sunscreen”), treating tragen in a more general sense of “have it on.” Both are understood, but Sonnencreme auftragen is more specific.