Using both both magicka and stamina skills is not recommended. You'll fail pretty badly at both. The reason is armor passives. You need at least 5 (nominally 7, but you can drop down a few pieces when you understand and can compensate for the cost increases) of each individual armor type to be effective (Light for magicka, medium for stamina). If you're under level 50 this doesn't matter much, but the higher level you go the more important it becomes to specialize.

That said, as long as you aren't heavy on the bow, a normal magicka build would be just fine with a bow in one weapon. The damage loss isn't that bad though you do lose the crit for the bow. You can either Crushing Shock Spam or Funnel Health spam as your primary spam skill and maximize magicka on the enchants (with attrib points in health until you feel comfortable. More health is always good)

Although you won't get much out of the bow build, as both destro and bow skills are comparable, neither has utility the other lacks. You'd be better off with a melee weapon or another destro/restro on your other bar to deal with situations your primary bar cannot.

Normally there are two ways you can go about setting yourself up:

Bar 1: Single Target (ranged or Melee, try not to do both. Also its good to note that range doesn't suffer from being ranged)
Bar 2: AoE Bar

or

Bar 1: Melee(and AoE) Bar
Bar 2: Range Bar

The first one is favored for most PvE, AoE is extremely important as the number of trash pulls are massive. The second bar style is more favored for PvP as you'll be in single target mode 99% of the time and you really only need 1 AoE (in your case, Sap) for those times it becomes useful.

With all that said, since you are under level 50, just level up everything. Learn everything. Figure out what does and doesn't work and how it works. Don't pigeon hole yourself into a single 'build' or a 'style', that crap doesn't work well in ESO. Ideally by level 50 you should have all class skill lines maxed and most weapon skills at least around 38ish (for the last ability) and every skill you can unlock ready to morph (morphs aren't very important for leveling up). If you can do this while leveling up you'll end up better off than the majority of other people since you now have experience with everything.

my NB has 1 stamina(DW) skill and 4 magic skills on her main bar,
but I spam the DW and use the magic skills situationally so a stamina build with just enough magika is what works for me.

I play a NB bow user and tend to have my first bar with the 3 bow skills and impale and swallow health while my second bar tends to have my utility and other class skills. If I need aoes I use a second bow and have them on the second bar. If not either have a resto staff or the 2nd bow equipped. Remember a bow does not have a penalty when using it up close it does however gain in damage when used at range.