Then what about altcoins that don't have support?
and if you look at the chart it has reached a new all time low and even if we buy it will still continue to fall,
and there is no bottom below, how? what should we do to buy that altcoin?
Altcoins also have support levels that break through just like bitcoin's support level. So we cannot know in advance whether the support level will stop the price, and for this reason we will have to place a stop order below this level. In this case, we will reduce our losses if the price continues to decline. As for new buy orders, they should be placed at the new support level and we will certainly get lucky sometime.