Phase I : The bread.
Bread is a product of fermentation, and it's made out of grain flour and water. Bread is not an industrial product, bread does not "come" pre-sliced or for that matter come at all. When you taste it you will know.
Either way bread is paramountly important to a good sandwich, and if you're trying to start with something that's not actually bread you've already failed.
Bread takes a spread. Normally we use butter, but salmon can't possibly hurt anything, can it ?
Phase II : The fillings.
You want some meat, some cheese and some veggie. In this implementation we use pastrami (beef, yes) which is an industrial product - proof that not all industry is bad - alongside Maasdam cheese (which is really Dutch Swiss so to speak) and sliced tomato.
Stick it together and enjoy!