Next does not have monster roles or guidelines when building encounters like 4e does

There are no monster roles anymore nor monster levels, in fact the only way to really gauge monster difficulty is look at its HP, AC, stats (because mods affect save rolls), damage output via attacks and spells, and the strength of its monster properties/abilities (immunity, resistance, special powers). All of the guidelines and tools you've come to expect in 4e no longer exist and nothing approaching them will exist in 5e until the DMG comes out in August.

My Suggestion

create a monster that has a nice HP pool and a multiattack power, but one that doesn't do too much damage so that you don't TPK the party if you get to go first. At low levels though, dying is very easy to do in Next, its almost unavoidable because of the influences that Next took from earlier editions of D&D.

Next does not have monster roles or guidelines when building encounters like 4e does

There are no monster roles anymore, they do give levels, but like the XP value they aren't as hard a guideline as they would've been in 4e. In fact the only way to really gauge monster difficulty is look at its HP, AC, stats (because mods affect save rolls), damage output via attacks and spells, and the strength of its monster properties/abilities (immunity, resistance, special powers). All of the guidelines and tools you've come to expect in 4e no longer exist and nothing approaching them will exist in 5e until the DMG comes out in August.

My Suggestion

create a monster that has a nice HP pool and a multiattack power, but one that doesn't do too much damage so that you don't TPK the party if you get to go first. At low levels though, dying is very easy to do in Next, its almost unavoidable because of the influences that Next took from earlier editions of D&D.