  We have used ALMA imaging (resolutions 0.1\arcsec-0.4\arcsec) of ground and
vibrationally excited lines of HCN and HC$_3$N toward the nucleus of NGC 4945
to trace the protostellar phase in Super Star Clusters (proto-SSC). Out of the
14 identified SSCs, we find that 8 are in the proto-SSC phase showing
vibrational HCN emission with 5 of them also showing vibrational HC$_3$N
emission. We estimate proto-SSC ages of 5-9.7$\times$10$^4$ yr. The more
evolved ones, with only HCN emission, are close to reach the Zero Age Main
Sequence (ZAMS; ages $\gtrsim$10$^5$ yr). The excitation of the parental cloud
seems to be related to the SSC evolutionary stage, with high ($\sim$65 K) and
low ($\sim$25 K) rotational temperatures for the youngest proto and ZAMS SSCs,
respectively. Heating by the HII regions in the SSC ZAMS phase seems to be
rather local. The youngest proto-SSCs are located at the edges of the molecular
outflow, indicating SSC formation by positive feedback in the shocked regions.
The proto-SSCs in NGC 4945 seem to be more evolved than in the starburst galaxy
NGC 253. We propose that sequential SSC formation can explain the spatial
distribution and different ages of the SSCs in both galaxies.
