Κράτα χαμηλή ταχύτητα και άναψε το φλας πριν στρίψεις αριστερά.

Both are informal singular imperatives, but they show different aspect:

• κράτα is the present imperative of κρατάω / κρατώ
  It suggests an ongoing action: keep / maintain
• άναψε is the aorist imperative of ανάβω
  It suggests a single action: switch on / turn on

So Greek is making a distinction that English usually does not show so clearly:

• Κράτα χαμηλή ταχύτητα = keep your speed low
• Άναψε το φλας = turn on the indicator

Χαμηλή is an adjective meaning low, and it agrees with ταχύτητα:

• ταχύτητα = speed
• it is feminine singular
• so the adjective must also be feminine singular: χαμηλή

The whole phrase χαμηλή ταχύτητα means low speed.

After κράτα, this phrase functions as the object of the verb, so it appears in the accusative. In this case, the accusative looks the same as the nominative for these words.

Greek often leaves out the article in instructions or general statements, especially with nouns like speed, attention, distance, and so on.

So:

• Κράτα χαμηλή ταχύτητα = keep a low speed

This sounds general and instructional. If you added an article, it could sound more specific or less natural in this kind of context.

Greek commonly uses ανάβω for turning on lights and signals.

Examples:

• ανάβω τα φώτα = turn on the lights
• ανάβω το φλας = turn on the indicator

Literally, ανάβω is related to lighting something, but in modern everyday Greek it is the normal verb for switching on lights, lamps, signals, and similar things.

Το φλας means the turn signal / indicator / blinker.

It is a very common everyday driving word in Greek. It is a loanword, and it is treated as neuter, which is why it takes το.

So:

• άναψε το φλας = turn on the indicator

After πριν meaning before, Greek normally uses the subjunctive, not the ordinary indicative form.

Here:

• στρίψεις = aorist subjunctive of στρίβω = turn
• στρίβεις = present indicative = you turn / you are turning

So πριν στρίψεις means before you turn.

The aorist subjunctive is used because the turning is seen as one complete action.

That is a very common learner question.

Usually, yes, the Greek subjunctive is introduced by να. But after certain words, especially πριν, Greek can use the subjunctive without an explicit να.

So:

• πριν στρίψεις = before you turn

Even though να is not written, the verb is still understood as a subjunctive form.

Here αριστερά is an adverb, meaning left or to the left.

With verbs of movement or direction, Greek commonly uses:

• στρίβω αριστερά = turn left
• στρίβω δεξιά = turn right

So in this sentence, αριστερά is not describing a noun. It is describing how / in what direction you turn.

You would use the plural/formal forms:

Κρατήστε χαμηλή ταχύτητα και ανάψτε το φλας πριν στρίψετε αριστερά.

Changes:

• κράτα → κρατήστε
• άναψε → ανάψτε
• στρίψεις → στρίψετε

This is the version you would use for:

• more than one person
• polite singular you

The sentence order is very natural and clear:

• Κράτα χαμηλή ταχύτητα = Keep a low speed
• και = and
• άναψε το φλας = turn on the indicator
• πριν στρίψεις αριστερά = before you turn left

Greek word order is often flexible, but in instructions like this, the straightforward order is the most natural. It keeps the sequence of actions clear:

1. keep your speed low
2. turn on the indicator
3. then turn left