Trimtech Chainsaw Blade Tensioning

For those familiar with the 2000W TrimTech electric Chainsaw, there's a yellow knob that is used to tension the chain to the bar. I'm never sure how tight to make the chain on the bar. Too loose and the chain slips off after 1 spin and too tight, I'm assuming strains the motor and damages both the chain and bar. Anyone with knowledge on this that can recommend an rule of thumb ?

Thanks guys