The sentence below is an example of using the past subjunctive in English; therefore, no tense is being used and, thus, verbs don't always have to correlate:

> If you **explained** what you *are* trying to achieve, I **would**
> recommend a kind of workaround.

The verb "to explain" has equivalent forms in the past indicative as it does in the past subjunctive:

> ***to explain***
> 
> **I explained:** first-person singular past indicative
> 
> **I explained:** first-person singular past subjunctive

In fact, the only verb in Modern English that shows a difference in its past subjunctive form when compared to its past indicative form is "to be":

> ***to be***
> 
> **I was:** first-person singular past indicative
> 
> **I were:** first-person singular past subjunctive

If you were to use "thou" or read "thou" in old literature, it does have a different form in its past subjunctive when compared to its past indicative form, but the rule isn't always followed in old literature like Shakespeare and the King James Bible because "thou" was on its way out when the rules of grammar were being written; however, in Old and Middle English, it was followed (circa A.D. 600 to circa 1400):

> ***to sit***
> 
> **thou sattest:** second-person singular past indicative
> 
> **thou sat:** second-person singular past subjunctive

Because the first verb of the protasis ("if" part of "if-then" statement, i.e. "explained") must be in the past subjunctive mood as well as the first verb of the apodosis ("then" part, i.e. "would"), this doesn't mean that the verbs of subordinate clauses have to be in the past subjunctive.  There are times when conjunctions are used such as "before", "until" or "if", etc. wherein the past subjunctive would have to be used, but, in this instance, that is not the case:

> If I **explained** it *until* I **were** blue in the face, you **wouldn't**
> understand what I ***am*** talking about.

I hope this might have helped you out.  Take care and good luck.