The polling stations will be open from 7 to 20h on June 28. Since the voting is happening using voting machines that tabulate votes as voters feed them into the machine, the count should be very quick after the polling stations are closed. The voting machines are set up to report results immediately to the general election commission, rather than any kind of tabulation by the local election officials intervening in the reporting.
This reporting structure suggests that barring any major mishaps or immediate challenges, preliminary results can be expected very quickly after polls close, but certainly on Thursday evening.
There does seem to be some dissatisfaction with the information about the election that is being distributed by the General Election Commission. However, flyers have been distributed to (Ulaanbaatar town centre) households that show samples of the ballot. At least the flyer that was delivered to the apartment we’re staying in was specific to the Sukhbaatar electoral district (#26).
On the national ballot, voters here in Sukhbaatar-Ulaanbaatar would mark two names (but organized by party) in the top section that casts their vote in the first-past-the-post riding election, and then mark a single vote for the part in the bottom section to cast their vote for nation-wide proportional representation party votes. For Ulaanbaatar voters, they would have a second page to cast their vote in the Ulaanbaatar city parliament elections on the same system, though with single-member districts. Note that the city election is being held in parallel with the national election for the first time.
Note that most electoral districts send two members to parliament (1 Arkhangai, 2 Bayan-Ulgii, 3 Bayankhongor, 7 Dornod, 9 Uvurkhangai, 11 Selenge, 13 Uvs, 14 Orkhon, 15 Darkhan-Uul,16 Khentii, 17 Tuv, 18 Khuvsgul, 19 Zavkhan, 20 Khovd, 22 Ulaanbaatar – Bayangol, 24 Ulaanbaatar – Khan-Uul, Bagakhangai, Baganuur, 25 Ulaanbaatar – Chingeltei, 26 Ulaanbaatar – Sukhbaatar), though there are six single-member districts(4 Bulgan, 5 Govi-Altai, 6 Govisumber and Dornogovi, 8 Dubdgovi, 10 Umnugovi, 12 Sukhbaatar), and two three-member districts (21 Ulaanbaatar – Songinokhairkhan, 23 Ulaanbaatar – Bayanzurkh).
The ballots themselves look like Scantron sheets where voters are required to fill in bubbles to mark their vote. In the polling stations, voters will register, receive their ballot, mark the ballot behind a privacy screen, feed this ballot through the counting machine, insert the paper ballot into a ballot box and exit the voting area, presumably being recorded as having voted, though whether this is by marking identification papers or fingernails or through some other method, I have not found out.