Ok, so to make this more simple to understand, I will try to stay on point.
To make the transition simple this is what I would do.
Clean and rinse sand, and clean and rinse sand some more. Unless you are using aquarium sand which says it does not need to be rinsed, like Eco-complete, adding link so you can see what I mean. If you are in the USA, there is free shipping, I don't know about to other countries. In my opinion, it is well worth the cost, good for a tank with plants.
Adding links so you can see for yourself, since English is a second language.
Amazon.com : CaribSea Eco-Complete 20-Pound Planted Aquarium, Black : Aquarium Decor Gravel : Pet Supplies
Or CaribSea Instant Aquarium- You do not rinse.
CaribSea - Instant Aquarium?
Rinsing is time consuming and you need to clean it again and again and again to get clear water.
##################
About 10 days before you will be changing the tank over, gently clean the filter pad in your filter with treated water. This will make sure you don't have to clean it the day you put it on the new tank. Saving as much BB as possible to keep your tank in healthy as possible condition.
I had a mini cycle when I changed over one of my tanks so I try to be very careful to save as much as possible.
Read all instructions if available, with new tank. Read through this info here so you will know what to do.
Decide if you will use your old filter AND the new filter when you get the new tank.
If you have a new filter I would use it AND the old one together. If that won't really fit for your tank I would use the old filter pad behind the new one to seed it.
VERY important not to rinse it at all. You could wipe off the edges with a clean rag or paper towel if there is gunk or slime on it. Even if it seems too dirty, it will be fine in such a big tank and you want all BB to be in there.
Start
Add your old tanks water to a big bucket, if you want to save more water, as long as it is pretty clean, save as much as you want to or have room for.
move the heater, unplug first and allow to cool, then add to bucket of tank water, replug
Add the air bubbler to the old water tank bucket, or see if your filter will hang on the side to circulate water.
Make sure to remove anything else which is plugged in.
Decide if it will be easier to tank out all decoration to catch fish and any invertebrates in the tank.
Remove fish or decorations first after you decide.
Then remove the fish or decorations which are still in there, to a new bucket.
Scoop out all gravel into a bowl, container or bucket.
Rinse and clean the tank, dry off and place it back where you will want it to set up.
Place any heavy stones or DW into the tank where you will want it.
Take your prepared, ready to add to your tank sand and add a scoop at a time, or if you can, pour it into the tank.
Add treated water (correct tank temperature) about 1/3rd of the way and adjust any DW or stones and any plants, plastic or live. Continue to add treated water until it is 1/2 full. Add additional saved old tank water.
You can test the old tank water and compare the new tank water and see if they are pretty much the same. If so then just finish by combining the fish and old tank water in the bucket with the new tank.
**If not really the same parameters, you need to acclimate the fish to the new water parameters.
Then remove about half of the water in your bucket (you may need to move the filter if the level of water is too low for the filter.
Start adding water by the 1/2 to 1 liter, or a couple of cups at a time every 10 minutes til nearly full.
Do the same as before, empty half of the water out of the bucket and put back into the tank. Then every 10 min add more water to fill the bucket. I am thinking of a 5 gallon bucket, which is what I always use.
Move everything electrical back over to the new tank, let the heater cool down again. Finish by wiping everything off and cleaning up, lol.
Make sure to put the heater back in.
Make sure all is functioning and hopefully all is well!