Gravitational wave detection gives information about events in the universe, that can not be observed, using electromagnetic radiation, like black holes merging with each other or with neutron stars. Since the first verified measurement of a binary black hole merger in 2015 it is proven, that more sensitive detectors will increase the number of detection, allowing us to improve our cosmological models. Such a planned observatory for the future is the Einstein Telescope (ET). Gravitational wave detectors like the ET with kilometres of resonator length rely on a good alignment of all optics, such that the beams overlap well and a good mode matching and alignment is achieved. Misalignment between carrier and squeezed light states induces optical loss and decreases the sensitivity. In the Hamburg ET high frequency tabletop prototype with arm resonators we use suspended, weighted and curved mirrors, that we steer, using several actuators. All four test masses have piezo motor driven marionette suspensions, that allow an individual alignment under vacuum conditions, with measured pendulum frequencies between 5.7 Hz and 7.2 Hz. The mirror position can be controlled with sub-nanometre precision. Thus it is possible to control alignment and mode matching precisely. Using the end mirrors, a lateral and vertical precision of 0.3 µrad can be reached with the suspension. The interferometer is aligned to contrast values greater than 99.9 % and the arm resonator mode matchings at least 95 %. Furthermore the Michelson fringe can be locked to a dark fringe, as long as the seismic excitations are small enough. An active stabilisation of the 30 t concrete block, which is the fundament of the experiment, was necessary. Additionally, the arm cavities can be held on resonance simultaneously by using a combination of the Pound-Drever-Hall technique, thermal actors and a piezo, that are installed in the test masses, to control the arm length. All locks are possible despite the compact design of the vacuum chamber with a height of only 23 cm. Moreover the sensitivity for gravitational waves at the frequency of one FSR (free spectral range) of the arm resonators, which is 164 MHz, is discussed. The prototype will help to examine the influence of mismatch on sensitivity, thermal lensing effects and other challenges in GWOs.