Lots of people have different ideas, I'm personally putting in 5 upgrading those 5 to level two, then 5 then upgrade to level two, etc. After that each one to level 4 individually
I'm putting mine in one by one, that's how I've been recommended to do it. And then when I have all 32, upgrade those to l2, then l3, etc.
If u get all t5 lvl1 first thats a plunder way. BUT if you ug one by one u get most stats for your money and in fact use less energy hitting bigger farms so will make more money
When putting in new tiers, it is best for plunder to put them in 1-by-1, BUT it is best for stats to max each individually before putting in a second, third, etc. Hope that helped. Other than that, it's completely up to you.