1) Does the top hat shaped rubber go on tire side ?
The rubber seal installs on the outside of the rim, the side exposed to ambient air, with the flat part against the T-valve.
2) Which was does the dome washer face ie dome towards wheel or away ?
The washer installs on the inside of the wheel, the side not exposed to ambient air, against the rim. It is a conical washer. Orientate it so that it is installed so that it creates a cone with the outside diameter of the washer against the rim and the inside diameter, where the through hole is, is domed away from the rim and against the nut. Tightening the nut collapses the cone so that the hole in the washer is forced towards the rim. This compresses the washer between the nut and the rim causing a constant tension fit similar to what a lock washer does.
3) Does the smaller diameter part of the top hat rubber go through the rim ?
Yes.
As installed configuration;
I would also suggest that the rubber seal be lubricated before installation, preferably with something such as an O-ring lubricant or similar. This reduces the friction between the seal and the rim during installation. This allows the seal to penetrate further in to the rim creating a better seal. It also helps to prevent the seal from getting damaged trying to overcome the force of static friction while the nut is being tightened. This allows the seal to bottom as much as possible initially during installation. As the rubber seal compresses over time, this will help to maintain the constant tension applied by the collapsed conical washer as there will be less initial compression for it to absorb. This will help to prevent the possibility of the assembly coming loose over time.