I applied thermal paste to my cpu and spread it out. I then put the cooler on top. Due to its position I had trouble feeding the retention plate through. So I pulled the cooler off and positioned the retention plate before placing the cooler on top of the cpu.
I smoothed out the thermal paste before putting the cooler back on. Is this a problem? I saw some guides that say once a cooler is positioned to not take it off.
You should be fine but the performance of the paste could be lowered - its best to put a drop of paste on the center of the CPU (about a grain of rice) and allow it to spread naturally. This is because the major amount of heat is from the center (underneath the heat spreader you have the diode) and to have the paste there, it'll be directly leaving the CPU. Putting it all over the heat spreader causes the heat to travel out first, then dissipate, and on top of that, create air bubbles. Not a big deal, again, but not optimal. You'll get it next time!