For a native metric user its really hard to know how to explain metric to someone who's accustomed to imperial measuments, but I'll try anyway.

As a measurement system the metric system is simplicity itself with everything a multiple of 10 i.e. 1 metre = 100cm = 10*10cm = 10*10*10mm (1cm = 10mm).

Metric math is simply just addition, subtraction, division and multiplication with normal base-10 numbers just like you would calculate money.

For example if we simplify a bit and say 1 inch = 25mm (I think its 25,4mm to be exact) then having a 4 inch board would equal to about 100mm which in turn equals 10 cm. If you want to rip that board in three equal width strips you just simply divide 100mm with 3 i.e. 100/3=33,33333mm (ignoring kerf width) you now aim at cutting at 33mm intervals to arrive at three 33mm wide strips.

Normally in metric you don't use exact fractions like in the imperial system you do i.e. you don't use notation of 33 1/3 instead you would write 33,33 in decimal and in woodworking you rarely need anything smaller than 1mm anyway, max 0,5mm resolution is achievable with even the sharpest knives much less with saws with a kerf of 2,2mm like the TS-saw blades.

In drawings it is customary to use millimetres i.e. table top lenght would be marked as 1200mm to denote a 1,2m long table top. Non-professionals often use centimetres instead and would write in the plan 120cm instead.

I find it easier to work in centimetres when you are on the better side of a metre i.e. 250cm instead of 2500mm or even metres when talking about long distances like 8.4m instead of 84000mm. Because everything is a multiple of 10 going from one unit to the next is just a matter of dropping or adding a zero to the end (or dividing/multiplying by 10).

Since the basic unit for all intents and purposes is 1 millimetre you don't need to worry about 1/32's or 7/16's etc.

You might want to learn some "standard conversion points" between metric and imperial. I use 25mm as an approximation for 1inch and multiples of an inch like 2x4 would be 50mm x 100mm, in plywood approximately 1/4" = 6,5mm, ½" = 12mm, 3/4" = 18mm (as standard thicknesses here are 4mm, 6,5mm, 12mm, 15mm, 18mm, 21mm, 24mm, 27mm and 30mm).

Probably getting a combination ruler/tape measure in the beginning may make the transition easier with visual aid to give you an idea how much is 37mm (1" 15/32).

I'm just as lost with imperial fractions and need a calculator or a

conversion table to make heads or tails out of those pesky fractions.

Once you figure the metric measurement system out you will notice that the same logic works for volume as well i.e. 1 litre = 10 decilitres, 1 dl = 10 centilitres, 1 centilitre = 10 millilitres etc. (though usually no-one uses centilitres - only litres, decilitres and millilitres)

Welcome to the world of simple maths