I want to get rank 40 asap how should I do it?

[Sanghelios]

Yea, only queue for english language in frontlines and everything else is just a grind. You will need around 270-300 frontlines games to reach rank 38-40. So we talking about 150-200 hours of grind (depends on queue times).

Wolfs Den challenge log is only worth it if you are rank 28+ and you have to win 3 out of 4 games (Easy as healer). Otherwise just stick with frontlines. And another tip is, you should try to be a leader. A Group without a leader will pretty often fail on easiest things (Wich leads to a loose, more or less).