Poker tactics

I have been playing for a couple of months. Never played on-line before. Only played rummy as a kid. I am seeing two major divisions of playing. I can't figure out what going on.
"Donk" behavior, (took me a day to figure out what it ment) Players who go all-in at the first 10 hands. These players usually wait till several players double or triple blinds. All-in, which makes many fold, including me even if I have an A K. I saw this today. The player had a 4 7, other 2 players had A 8 & A 3, this guy won the hand with a straight. This was all-in pre flop. I don't understand this. Is this just aggressive tactics to build up chips or bad playing being rewarded.
I understand the the tactics when you get to the 1k -3k blind level. You want to get to the finish line. Yesterdays freeroll I ended up 124 out of 12k. Just a couple short of the 99 to the next level. I had went all-in several times. though I called and didn't raise when I thought I had the best hand.
Too many players complain about the "donk". They don't think that they are winning or at lest getting in the money.
I don't know what to think. I don't know the best way to play.

There are a lot of good strategies at the link below

Poker Strategy - Poker Theory, Poker Articles, Strategies & Tips.

Also what stakes are you playing? The level of play at different levels is vastly different. I play micro S&G's so I usually spend the first level or two of the blinds letting the maniacs chew each other up and play a super tight game. After the maniacs have thinned the tables tend to tighten way up and I go from there.

"Yesterdays freeroll"

There is your answer as to why they (the all-iners) do this. It's a free game so they just gamble and hope to get lucky.

There is no 'best' way to play except the way you feel most comfortable with.

Some players are aggressive all the time and play any two cards (ATC) and bet aggressively to put of their opponents, others play tight and select which cards they play and only play in position (on the button, blinds etc).

The best bit of advice i can suggest is play your game the way you want to, dont change your game to suit or match others. Mix it up by all means - but when you want too.

As for play in freerolls well - not everyone in the asylum is a patient but sometimes you wonder lol