You need to make a home made accumulator out of a pop bottle, two presta tyre valves and some plastic tube.
You need to drill two holes in the pop bottle lid so that you can screw both valves through. The plastic tube goes between the tyre valve and one of the valves. The pump attaches to the other valve.
You pinch the plastic tube so you can pump the pop bottle up and then release the pinch on the plastic tube to release the pressure into the tyre. Its gives a sudden surge needed to pop the tyre on to the rim.
There are other posts on it somewhere on here – I have no photos of mine, but it works every time and makes tubeless easy.