I have a packet of Muska Böreği that I bought recently. The instructions say:
Paketi açtıktan sonra 5 dk. havalandırarak dinlendiriniz
Am I right this means something like:
Allow to rest for 5 minutes after opening the packet?

Quick as you can because I want to cook them

i would imagine so as the first bit means after the packet allow 5mins... so probably

No, it is the -dik suffix in açtıktan. Because the -dik suffix is a past tense participle it looks and sounds like simple past tense but it isn't. Simple past tense doesn't build nouns, adjectives or adverbs from verbs but its participle "-dik" does.

V-madan önce : before V-ing
V-dikten sonra : after V-ing

example:
gelmeden önce : before coming
geldikten sonra : after coming

Now, you might say, "OK, I understand that the -dik is the past participle and builds verbal adjectives or advebs but what is the "den"?

The "den" in gelmeden or the "ten" in geldikten is connected with the following word, sonra or önce.

In other words "-den önce" or "-den sonra" need to be understood as structure on its own.

-den önce : before something
-den sonra : after something

You can use these on any noun, including verbal nouns.

benden önce : before me
senden sonra : after you
yarından önce : before tomorrow
okuldan sonra : after school
gitmeden önce : before going
dinledikten sonra : after listening

This above is a typical example of the -dik suffix.

"açtıktan sonra", "gelmeden önce", "geldikten sonra", "geldiğin zaman", "dinlediğin zaman", "baktığın için", "sevdiğim için",...

All these are adverbial clauses. All have an adverb and a past tense participle. All verbs in these examples have the same -dik suffix. In some cases the -dik suffix changed to t version (according consonant harmony) and in some cases the k changed to ğ (according consonant mutation) but all have the same suffix.

Poor Bod!
Did you eat your Muska Böreği because I think 5 minutes were past long before all these grammar explanation. If I was you, I just would respond to the word 'sonra' but thank you anyway, if not you I wouldn't know about all these suffixes.
Thank you Erdinç for the great lesson

What about the suffixes in
havalandırarak dinlendiriniz

They both have the -dir suffix. Is this the third person singular possessive suffix??? And is the -iniz suffix added to make this into a general instruction???

havalandırarak dinlendiriniz
Set it aside by ventilating it

Glad to hear it. Next time do not wait for grammar rules to eat, do it as you wish, never fallow the instructions.

I understand you very well. Usually I do not fallow the instructions.
Men are better chefs.

Hi Bod,
This -dir suffix is the causative suffix.

Examples:
almak (to get) > aldırmak (to make somebody get)
bakmak > baktırmak (to make somebody look)
yapmak > yaptırmak (to make somebody do)

This issue is very smillar to passives:
germek (to stretch) > gerilmek (to be stretched)
bozmak (to break down) > bozulmak (to be broken down)

Now, the question is, "Is aldırmak a verb on its own or is it a variant of almak?" Smillarly, "Is 'gerilmek' a verb on its own or is it a variant of germek?"

These are a bit difficult to tell. My approach is to consider all those causative or passives as independent verbs. Therefore there is nothing wrong to say the infinitive of havalandırarak is havalandırmak.

In most cases the causatives or passives have different meanings then the version they were derived from. This means the causatives ort passives have such meaning that are not included in the definition of non-causative or non-passive versions. Those causative and passives need their own definitions. They are independent verbs. In some cases a verb might be omited from language but its passive or
causative verb can survive.

On winmekmak we couldn't prevent passives to take passive a second time. There is no causative conjugation at all so the problem was only with passives although the issues are the same.