hey doors, here's how baahun/chhetri do those stuff. i don't know much about newaars, mongolian ethnicities and all those countless other ethnicities, but it should be similar although not exactly the same:

1. if you are planning to grow jamara, get some soil, a flower pot (or those tin bakewares!) and some seeds (mix of rice, wheat, barley, corn or whatever you can find among these). on the day of ghatasthapana, sow the seeds, put some water in and do "puja". 
2. if possible, keep the that pot/tray somewhere in dark and worship every morning - sprinkle some water, light the diyo, perform a typical puja until the day of dashami. you don't have to worry about the diyo going off after a while i.e. you don't have to keep it lighted for 9 days.
3. if feasible, go to durga temple, if not go to some other temple, if that's not possible, print out a picture of durga and worship every morning (usually done after you worship jamara)
4. if you go to temple, on the day of fulpati, bring some prasad (flowers/fruits) that other devotee's offered and put the flowers on the beam of your main entrance (dhoka maathi siurine, or tape le taasne!). if not, use the flowers you offered that morning to the picture of durga
5. on asthami or nawami, you'll worship your vehicles/tools, if possible and you want, sacrifice a chicken, pig, raago, duck, or bokaa. i prefer to break a coconut instead and use the water inside to mimic the blood of animals and the coconut flesh to represent the flesh of animals as prasaad.
6. on the day of dashami, you worship the jamara as usual, you worship durga, and you harvest all/some of your jamara - cut, not uproot. first thing, you stick some jamara on one of the main poles /beams of your house (nepalima thaam or dalin) using akshata as glue.  since that might not be possible here, you can just use a paper plate and stick jamara on it and hang it somewhere, after that worship it. you may discard it after dashain is over. after doing that sticking thing, tika begins. and if you are giving some jamara to your friends or relatives, make sure you don't give any before the sticking thing.

*** i've used puja/worship interchangebly. 
here's a typical way of doing puja just in case you don't know:
0. take a bath, it's always a good thing to do in the morning
1. sprinkle some water over/around whatever you are worshipping
2. if it's a statue/framed picture, people usually wipe off the tika they put on the deity the previous day so that the face of statue/picture doesn't get covered and look nasty after a few days (not necessary though)
3. light a diyo >> put a pair of batti with it's tip (the end which your fingers twist while you are making batti using cotton) protruding a little bit from the mouth of diyo, put another pair inside the diyo perpendicular to the first pair of batti (the two pairs of batti should make roughly "+" sign); put some oil in (any oil should work) and light the tip that's protruding out
4. first, put tika on the statue/pic with keshari (yellow), and then abir (red), then akshata (rice grains+red), next is the flower(s), then offer what you have - fruit(s)  (cheap alternative is sugar..haha), and finally coin(s) if you wish to make a wish or you just wish to offer coin without making a wish 
5. light a dhoop, move your hand around the deity as if you are trying to make them smell the dhoop
6. if you have, ring the "ghanti" a few times, and shankha too, if you have but that might scare your neighbors
finally, bow to the deity with your hands saying "namaskar"
and you're set!
 btw, akshata for everyday puja can me made using just rice grains, abir, and some water. but for dashain's tika, you want it to stick for long time on your forhead. so, here's how you make it just in case you don't know - rice grains, abir, use dahi (plain yogurt from grocery will do just fine) instead of water, and add some sugar (if you are using 1 cup rice grains, use like 1-1.5 table spoon of sugar). and mix well. if the mixture is thin, add more rice, if it's too thick and dry, add some water or yogurt.

hope that helps.
Happy Dashain to all.