Handbook of ROCOR Liturgical Practice:

When multiple readings of the Apostle or Gospel are appointed (or when a single reading is repeated in a second language), how are the second and subsequent readings introduced?

When there will be two or more pericopes of the Apostle, or two or more pericopes of the Gospel, only the first is announced. While by intonation (or an alternating of Readers) the end of one reading is indicated and the next begun, second and subsequent readings are not introduced, but simply begun with the appropriate word or phrase (e.g. ‘Brethren…’, ‘At that time…’). This is also true when a single reading is repeated in a second language: only the initial reading is introduced; its repetition in a second language begins without an introduction.

For the sake of clarity this means that, for example, when two Apostle readings are appointed, the pattern is thus:

Deacon: Wisdom.
Reader: The reading is from the epistle of the Holy Apostle N. to the NN.
Deacon: Let us attend.
Reader: Brethren… and then the first reading. At its conclusion he denotes the ending with a rising and lowering of his voice in the usual way, then immediately begins the second reading: Brethren…

If there are two Readers, each appointed for one reading, the pattern is thus:

Deacon: Wisdom.
Reader 1: The reading is from the epistle of the Holy Apostle N. to the NN.
Deacon: Let us attend.
Reader 1: Brethren… and then the first reading. At its conclusion he denotes the ending with a rising and lowering of his voice in the usual way. Then immediately:
Reader 2: Brethren…

When multiple Gospel readings will be read:

Deacon/Priest: The reading is from the Holy Gospel according to N.
Choir: Glory to Thee, O Lord, glory to Thee.
Deacon/Priest: Let us attend.
Deacon/Priest: At that time… and the first Gospel reading. At its conclusion he denotes the ending with a rising and lowering of his voice in the usual way, then immediately begins the second reading/language: At that time… without introducing the reading (even if it should come from a different Gospel account: the readings are announced only via the first reading, naming the Evangelist of that first reading alone).