First you work out the number of moles in fluorine. You don't need to worry about sulphur as it is in excess, (so loads is available - think of it as an infinite amount available for you.).
To work out number of moles, you require the formula:
moles = mass / molar mass
I see you have correctly worked out molar mass for fluorine, which is 38.
Mass is given to you, so you plug it in the formula.
When you divide 0.950 by 38, you get 0.025 moles.
According to stoichiometry, for 3 fluorine molecules, you have 0.025 moles
But Sulphur hexafluoride, has 1 mole in front of it.
So you need divide 0.025 by 3 to find amount of moles for 1, which is 8.333333333*10^-3 moles
I see you have correctly worked out molar mass for sulphur hexfluoride, which is 146.1
Again, using the same formula, rearrange to make mass the subject, which is mass= moles * molar mass
You have molar mass and moles, hence plug it in, so 8.333333333*10-3 multiplied by 146.1 is 1.2175g
That is the amount of sulphur hexafluoride produced
You said 3 s.f., so you would answer as 1.22g