Ignore the hoolah on the media and idiots in /r/investing. Dollar Cost Averaging. Just pick a dollar amount each month and put it in like clockwork. I'm assuming you won't be looking to retire for another two decades at minimum so we're playing the long game here. Remember, even in 2008 nobody lost money in the markets unless they panicked and sold.
Dollar cost averaging made sense in an Era of decreasing interest rates. If you want to see what happens to dollar cost averaging when you have stagflation and a huge bursting bubble take a look at the Japanese market. Socks really seem to have be a strictly speculative/gambling assets where their price is dependent not on fundamentals of growth or profit but of but on the hope that you can sell them later to some greater fool. As long as there is an unlimited amount of money coming out of the FED stocks will grow, but as soon as the spigot closes or the flow decreases the supply of greater fools really dwindles.